Such aids for osteosynthesis, especially metallic aids, serve for the inner fixation of a fracture. In the case of such completely covered or incompletely covered osteosyntheses, disinfection is a particular problem, since the aim must be to bring the antibiotics as far as possible directly to the site of infection.
A carrier substance provided with an antibiotic, specifically a poly-(methyl methacrylate) to which gentamycin has been added as the antibiotic, has been disclosed in a publication ("Gentamycin-PMMA-Kette", "Gentamycin-PMMA-Kugeln" ("Gentamycin-PMMA Chain", "Gentamycin-PMMA Spheres") from E. Merck, Darmstadt 1977); this carrier material ensures protracted release of the antibacterial active ingredient in reliable bactericidal concentration and ensures that despite release of the antibiotic taking place the external shape of the carrier material is retained.
This known carrier material for the antibiotic has been employed, for example, in the case of bone infections, specifically by introducing spheres, drawn up on a surgical wire, into the bone marrow cavity. The occurrence of bone infections interferes in a significant percentage (3-15%) of cases in conservative or operative treatment of open and closed fractures of the limbs. Not only is the osseous fracture consolidation hindered or greatly retarded as a result of this, but, frequently, local destruction of the bones is also associated therewith and this can give rise to frequent operations. In addition to the long treatment period, cosmetically unattractive changes in the skin and disturbances in the normal body proportions can usually not be avoided and in individual cases this disturbance of health can necessitate an amputation. The combination of conventional aids for osteosynthesis with gentamycin-PMMA chains inserted at the same time does not permit an adequately high concentration of active ingredient at the point of contact between metal and bone. On the other hand, the space requirements of the aid for osteosynthesis are in themselves already a great problem when covering, for example, an arm or lower leg with soft tissue. The additional insertion of chains would signify a considerable circulatory disturbance in the bone nourished by the periosteum and would hardly permit the necessary covering of the aid for osteosynthesis with soft tissue. Moreover, the removal of these additional chains involves a complicated and difficult operation.
In German Offenlegungsschrift No. 2,305,442, an implant for fixing inside long bones is described and it is said that cements and plastics should be avoided as fixing material in the bone.
In the literature cited above it is proposed that a pharmaceutical depot be installed at a suitable point in the implant, so that, after the operation, inflammation due to pathogens can be effectively suppressed. In the said literature it is not indicated how this pharmaceutical depot should be made up, so that it can be assumed that the inventor makes use of the teaching according to German Offenlegungsschrift No. 2 154 272, in which such a depot of pharmaceuticals by incorporation in gelatine is proposed.